Sound recording oscilloscope



Nov. 22, 1938. H. L. COUGHLAN 2,137,768

SOUND RECORDING OSCILLOSCOPE F11 6 March so, 1935 3 Sheets-Sheet 1JVQmZQZ lama/u? (big/6X62 Nov. 22, 1938 H. L. COUGHLAN- v SOUNDRECORDING OSCiLLOSCOPE Filed March 50, 1935 3 Sheets-Sheet 2 10a lam/aZgozaz o an NOV. 22, 1938. H L CQUGHLAN 2,137,768

. SOUND RECORDING OSCILLOSCOPE Fil ed March so, 1955 3 Sheets-Sheet 3Patented Nov. 22, 1938 UNITED STATES PATENT GFFliIE Application March30, 1935, Serial No. 13,986 In New Zealand April 6, 1934 16 Claims.

his invention relates to sound recording oscilloscopes and moreparticularly to the production of what are termed sound films or talkiefilms for use with cinematograph production wherein the pictorial actionis produced with accompanying sound which occurs with or is coordinatedwith the pictorial representation. In sound motion picture practice itis customary to produce a cinematograph film record on which there is aseries of pictorial representations and at the same time to produce arecord of accompanying sound, the sound record being commonly in theform of a continuous record along the side of the film i. e. by the sideof the pictures. The

' sound record may be of any known type, for example it may be thevariable density type, or the variable contour (width) type, or acombination of both types. In some cases the sound record is made upon afilm or other recording medium separate from the picture film; and insuch latter case of course, the sound reproduction must be accuratelyco-ordinated with the picture film projection so that an observer oraudience will receive the impression of simultaneous reproduction ofscenes in the picture and the proper accompanying sound.

Further, in sound motion picture production and recording of sound ofvariable density type or variable contour (or width) type, recordingmeans such as oscilloscopes or the like have been promoted and used todeal with sound-frequency electric currents passed to and through suchmeans from a microphone, along with its associated apparatus.

It is an object of the present invention to provide apparatus for thesaid recording of sound motion picture films by a high-frequencyoscilloscope or the like wherein sound is recorded or traced in eithervariable contour (width) type or variable density type with preferencefor the former type, upon the sound track of a motion picture film. Toachieve this object reflected light is employed whereby a sound track isproduced photographically on a photo-sensitive surface of a suitablyarranged material, said photographically produced sound track possessingthe major attribute of modern tone-quality performance, while the said(high frequency) oscilloscope is more reliable, rugged and tremendouslyrigid compared with moving coil type sound recorders made hitherto.

A further object of the present invention is to provide in a reflectedlight oscilloscope means which will not readily break down, for thetensioned parts will not need to be strained near to their rupture point(as in previous devices) in order to stop spurious vibrations to thedetriment of the primary function of the device.

' With these objects in view the present invention provides an improvedoscilloscope or the like having means creating a magnetic field, a stripor ribbon of non-magnetic metal supporting a light reflector held insaid field and wherein said strip or ribbon is constrained along theedge at least on one side, so that a hinge is formed near where thestrip or ribbon is constrained as aforesaid.

The invention will now be further described with reference to theaccompanying drawings in Which:--

Figure 1 is a front elevation of the improved oscilloscope with thecasing partly cut away to show the interior,

Figure 2 is a plan of Figure 1 with the cover and its terminals removed,

Figure 3 is an enlarged cross section of the pole face plates and thestrip or ribbon througn line 3-3 in Figure 1, and,

Figure 4 is an enlarged front elevation of that portion of the strip orribbon which passes through the gap formed by the pole face plates, and

Figure 5 is a perspective view of the gripper, while Figure 6 is a viewtaken on the line 6-$ in Figure 1, without the adjusting mounting.

With reference to the drawings, coils I, la having poles 2, 2a aremounted on a base 3 and may be secured to the latter by bolts 4, 4a andnuts 5, 5a or as illustrated in the drawings insulated spacer bars 6 maybe inserted between the poles 2, 2a and the base 3 so as to separate thepoles from the base and the whole held together by the bolts 4, 4a andnuts 5, 5a. In this latter connection the lower insulated spacer bar 6has an extension secured to the base 3 by bolt 6a and nut 611. By suchan arrangement an intense magnetic field can be created by the coils andtheir plates as hereinafter provided.

The poles 2, 2a are provided with pole face plates 1, 8 which convergetowards each other and are adjustable on, and attached to the poles 2,in by screws la, 8a. The pole face plate I has a turned out portion 9(see Figure 3) and the latter has a notch 9a in the central part of theouter end. The pole face plate 8 has a gripper I!) with a notch Illa inthe central part of one end, so that the notches a and Illa oppose eachother. The other end of the gripper III has a sharpened turned in endinglllb preferably accommodated in a groove l l in the pole face plate 8;and the gripper I'll has holes to take screws l3, l3a which thread intocorresponding screw thread-ed holes in said pole face plate 8 to holdsaid gripper l0 thereon. Insulating material 82 is placed between thegripper it and the pole face plate and preferably also, the gripper itis adjustable on the pole face plate 8 by enlarging the holes in thegripper In so that the latter is free to move sidewise or slide on thescrews 13,

I3a. By such arrangement an intense magnetic field of steady value isproduced across a narrow gap I4 thus formed between the ends of the poleface plates I, 8 in such a manner that all the available flux is passedacross and concentrated in such gap.

Also, mounted on the base 3 by means of the spacer bars 6 and betweenthe two poles 2, 2a is a carrier which holds a strip or ribbon ofnonmagnetic metal, preferebaly duralumin in the narrow gap I4 formedbetween the opposing ends of the pole face plates I, 8 as aforesaid.

The carrier comprises a back plate I5 attached to or an extension of oneof the said spacer bars 6, an electric terminal having screws (20a)attaching an electric cable end 2| to the bottom end of the back plateI5, a shoulder Il mounted by screws Ila above the terminal and below thepole face plates I, 8, a shoulder I8 mounted on the back of plate I5above the pole face plates I, 8 and an adjustable strip or ribbontensioning means bolted to the upper end of the back plate I5.

The electric cable end 2| secured to the bottom end of the back plate I5has a strap of insulating material I 6a and a bar or plate 20 caughtunder the screws 20a, and the electric cable end 2| of electric cable2Ia is held between said insulating material I6a and said bar or plate20. Also the bottom end of the strip or ribbon 23 is held between theending 2I and said bar or plate 28.

The shoulder I! mounted by screws I'Ia. above the terminal I6 has arounded protuberance 22 over which the strap of insulating material IBais drawn and held on the shoulder Il by the said screws Ila. so thatpreferably said insulating material I5a covers the whole of the outersurface of the shoulder II. The outer face of the shoulder I'I standsout from the back plate I5 until it is flush with or in the samevertical plane as the outer surface of the pole face plate 8.

The shoulder I8 mounted above the pole face plates '1, 8 has an outersurface I 811 flush with and in the same vertical plane as the outersurface of the pole face plate 8 and therefore is also in the same planeas the outer face of the shoulder I1. Further the shoulder I8 has a cutaway surface I81; in which near the sides are screws 24, 25 threadedtherein. Caught under screw 24 is a slotted washer 2 5 having anoutturned lug 21 by which the strip or ribbon 23 can be guided ashereinafter described. The top end portion of strip or ribbon 23 iscaught under the slotted washer 25a by the screw 25.

The adjustable strip or ribbon tensioning means bolted to the upper endof the back plate I5 comprises two posts 28, 29 mounted on a segment 3|!and joined by a bar 30a, and said posts and bar support a bridge 3|having a hole 32; said parts 28, 29, 38 and 3| form a recess in which isa slide 34 terminating at its lower end in a strip or ribbon carriershackle 35 and at its upper end in a threaded bolt 35 which is movablethrough the hole 32 against a spring 31 under compression between thetop of the bridge 3| and a collar 38 which latter is held upon the bolt35 by a nut 39.

The strip or ribbon 23 caught at its lower end as aforesaid," is drawnover the insulating material Ilia, through the gap I4 between the endsof the pole face plates 7, 8 around the outside of the lug 21, passedthrough the carrier shackle 35 to the screw 25 where the top end portionis secured as previously set forth. It will be appreciated from theforegoing that with a strip or ribbon mounted as aforesaid, adjustmentof the lug 21 by movement of the slotted washer 26 will vary theguidance and the position of the strip or ribbon 23 through the gap I4between the ends of the pole face plates I, 8; and that the strip orribbon 23 can be tensioned by screwing the nut 39 upon the bolt 36 andagainst the collar 38 and the spring 31 whereby the compression of thelatter draws the carrier shackle 35 up, which action tensions the stripor ribbon 23 between its holding means comprising the bar or plate 20and the cable ending 2| at the bottom, and the screw 25 at the top.

It is an essential part of this invention that the strip or ribbon 23 isheld or constrained particularly along one edge while the other oropposite edge is free. With such object in view the gripper I8 isprovided as a means for carrying the same into effect; but it will beappreciated that other means could be usefully employed for thispurpose, and the invention is not confined to the particular meansherein set forth. In effecting this purpose the edge 23a. of a strip orribbon 23 is constrained between the gripper I and the pole face plate 8by screws I3, I3a and such constraining is carried out between insulatedsurfaces by insulating material 50 atttached to the surface of the poleface plate 8 and by insulating material I2 attached to the inner surfaceof the gripper I0. Further, the edge 23a of the strip or ribbon 23 mayhave notches or scallops 23b and preferably only the parts or portions23c of the strip or ribbon 23 between said notches or scallops 23b arecaught by the gripper between insulating materials 50 and I2 asaforesaid, so that flexibility in the nature of a hinge is added to thestrip or ribbon 23 when and where it is constrained. The strip or ribbon23 is also provided with alightreflectingsurface 40 which is ailixed tothe strip or ribbon 23 so that when the latter is tensioned asaforesaid, said reflecting surface 40 registers with the notches 9a andla.

The back plate I has an electric terminal 4| a which is preferably anearthing terminal for cable 4| so that electric current or impulseseither continuous or alternating can pass from the terminal I6 throughthe strip or ribbon 23, and to the said earthing terminal Ma.

The coils I, Ia are provided with electric cable leads 42 and 42arespectively and through which leads, the said coils are electricallyenergized in the usual manner well known in the art.

The base 3 is fastened to the inside bottom of a container 43 in suchposition that the strip or ribbon 23 is immediately behind a lens 44held at the correct angle of focus in the side of the container 43.Attached underneath the bottom of the container 43 is an adjustablemeans for adjusting a beam of light reflected from the reflectingsurface 40 when such beam is cast through the lens 44, said adjustablemeans being well known in connection with Oscilloscopes.

Preferably sufiicient oil is placed in the container-43 so that theparts mounted on the base 3 are submerged within the clear oil bath toreduce the natural vibration period of the ribbon-reflector assemblywhich in a correctly adjusted unit will occur at an extremely highfrequency.

A cover 45 which fits upon the top of the container 43 has electricallyinsulated terminal buttons 46, 41, 48 and 49 to which are attached cableleads 42, 2| a, 4| and 42a respectively. The cover is provided with aconvenient hole I9 immediately above the nut 39 so that the latter canbe turned for tensioning purposes as hereinbefore described;

and said hole is provided with a closure or cap (not shown). v

In operation, light from a steady source preferably one of highintensity and focused by means of a suitable lens system (well known inthe art) is directed through the lens 44 upon the reflecting surface 40from where the reflected light is reimaged at the correct position upona light sensitive fllm or photographic negative. Continuous oralternating current, passing through the edgewise constrained strip orribbon 23 will deflect said image to a degree dependent upon the valueof the applied E. M. F. and frequency and the variation in thedeflection of the image is optically recorded by well known suitablephotographic means.

What I do claim and desire to obtain by Letters Patent of the UnitedStates of America is:-

1. In an instrument of the oscilloscope type, means for producing amagnetic field, a vibrating light reflecting means arranged in saidfield, means for tensioning said light reflecting means above and belowsaid field producing means, and fixed means applied along one edge ofsaid light reflecting means to constrain the movement thereof.

2. In an instrument of the oscilloscope type, a magnetic element forproducing a magnetic field, a vibrating light reflecting means arrangedin said field, means for tensioning said light reflecting means aboveand below said magnetic element, fixed means applied edgewise of saidlight reflect ing means to constrain the movement thereof, saidconstraining means being arranged parallel to the pole faces of themagnetic element and being applied along one side of the lightreflecting means the other side of the light reflecting means beingfree.

3. In an instrument of the oscilloscope type, means for producing amagnetic field, light reflecting means arranged in said field, meansapplied along one edge of said light reflecting means to constrain themovement thereof, and upper and lower means disposed above and belowsaid magnetic fleld for guiding said light reflecting means, saidconstraining means being applied to said light reflecting meansthroughout its length within said magnetic field.

4. In an instrument as claimed in claim 3, an electric terminal, meansconductively associated with said terminal for securing one end of saidlight reflecting means and means for longitudinally tensioning the lastmentioned means.

5. In an instrument as claimed in claim 3, an electric terminal, meansconductively associated with said terminal for securing one end of saidlight reflecting means, said securing means being below the lowerguiding means, and means for longitudinally tensioning the lightreflecting means disposed above the upper guiding means.

6. In an instrument as claimed in claim 3, an electric terminal, meansconductively associated with said terminal for securing one end of saidlight reflecting means, said securing means including, a bar andinsulating means, said bar being disposed on said light reflectingmeans, said terminal including an electric cable, the end of which isdisposed beneath said bar and light reflecting means, and saidinsulating means being disposed beneath said cable end and means forsecuring said bar to said light reflecting means.

'7. An instrument as claimed in claim 3, wherein said lower guidingmeans includes a shoulder the lower outer edge of which is rounded, andinsulating means covering said shoulder.

8. An instrument as claimed in claim 3, wherein said lower guiding meansincludes a shoulder, the outer surface of said shoulder being in thesame vertical plane as said constraining means.

9. An instrument as claimed in claim 3, wherein said upper guiding meansincludes a shoulder, the outer surface of said shoulder being in thesame vertical plane as said constraining means.

10. In an instrument as claimed in claim 3, two screw bolts fastened tosaid upper guiding means, slotted washers engaging said screw bolts, oneof said washers being provided with an upturned lug for guiding thelight reflecting means, the other screw bolt being adapted to secure theupper end of said light reflecting means.

11. In an instrument as claimed in claim 3, means for longitudinallytensioning said light reflecting means, said means comprising a segment,posts in the segment, a bar joining the posts, a bridge provided with ahole supported by said posts and bar, said segment, posts and bridgeforming a recess, a slide disposed in said recess, a carrier shackle forthe light reflecting means at the lower end of the slide, and a threadedbolt at the upper end of the slide, a collar fixed to said bolt, aspring under compression mounted on said bolt between said bridge andcollar, said bolt being movable through said hole against the action ofthe spring.

12. An instrument as claimed in claim 1, wherein said means forproducing a magnetic field comprises coils, pole pieces mounted on abase and passing through said coils, adjustable pole face platesattached to the ends of said pole pieces and cables leading to saidcoils.

13. An instrument as claimed in claim 2, wherein the means for producinga magnetic field include pole face plates turned inwardly to form anarrow gap through which said light reflecting means can pass, and agripper member fixed to one of said plates for securing one edge of saidlight reflecting means onto the face of the said plate.

14. An instrument as claimed in claim 2, wherein the means for producinga magnetic field include pole face plates turned inwardly to form anarrow gap through which said light reflecting means can pass, a grippermember fixed to one of said plates for securing one edge of said lightreflecting means onto the face of the said plate, and insulatingmaterial disposed between the gripper member and the light reflectingmeans and between the pole face plate and light reflecting means.

15. An instrument as claimed in claim 2, wherein the means for producinga magnetic field include pole face plates turned inwardly to form anarrow gap through which said light reflecting means can pass, a grippermember fixed to one of said plates for securing one edge of said lightreflecting means onto the face of the said plate,

and insulating material disposed between the gripper member and thelight reflecting means and between the pole face plate and lightreflecting means, said pole face plate being provided with a groove andsaid gripper having a turned-in end to associate therewith.

16. An instrument as claimed in claim 1, wherein said light reflectingmeans include a metallic strip and a reflector carried thereby,saidstrip having a scalloped edge, said constraining means coacting withsaid scalloped edge.

HAROLD LEONARD COUGI-ILAN.

